Microtubules are hollow polymers made up of tubulin subunits. Neurons, like other eukaryotic cells, contain a pool of free tubulin subunits and a pool of the microtubule polymers. These two pools dynamically exchange with one another such that microtubules undergo bouts of assembly and disassembly.n neurons, microtubules are also nucleated at the centrosome (located in the cell body of the neuron), but the microtubules are then severed from the centrosome so that they can be deployed into axons and dendrites.
If the parent makes this election, the child does not have to file a return. Earned and Unearned Income. If a child has both earned and unearned income, he or she must file a return (2016 and 2015) if: unearned income was over $1,050; earned income was over $6,300, or
Married people that file separate tax returns were required to file if income was $3,700 or higher. Income minimums are slightly higher for people age 65 or older. Single filers 65 and older did not have to file a return if they made less than $10,950.he IRS reports that single dependents under age 65 were required to file tax returns for the 2011 tax season if earned income was more than $5,800 and if unearned income was more than $950.